Some plants of the botanical family Cucurbitaceae, found mostly in China and other parts of Asia produce intensely sweet fruits. These fruits have a characteristic intense sweetness due to the presence of certain terpene glycosides; natural materials which can provide sweetness. These compounds, (triterpene glycosides) known as mogrosides and siamenosides, are described and characterized, by Matsumoto et al; Chem. Pharm Bull., 38(7), 2030-2032(1990) and R. Iasai et al., Agri. Biol. Chem., 53(12), 3347-3349 (1989).
A fruit in the Cucurbitaceae subfamily, called Luo Han Guo or Rakanka, is produced by the plant Siraitia grosvenorii found in southern China. Extracts of the fruit and the dried form of the fruit have been used in edible products. Luo Han Guo has been known as a naturally sweet fruit for many years. A gum syrup made with extracts of Rakanka combined with stevia (a low calorie sweetener) is known in Japan.
Traditionally, these fruits are dried and stored in the dry state until used. The dried fruits are used whole, as extracts, or in powdered or block forms. The prepared block form "Luohanguo Chongji" is reported to be a popular treatment for colds and the dried fruits are used in a variety of traditional Chinese medicines, see for example, The Encyclopedia of Traditional Chinese Medicine (Jiangsu New Medical College, 1977, Zhongyao Dachidian People's Publishing Co., Shangai, China).
While the drying process preserves the fruit and removes most of the objectionable flavor from the fresh fruit, it also causes the formation of bitter, astringent and brown flavors. These flavors restrict the use of the dried fruits and dried fruit extracts to the preparation of dilute teas and soups and products to which sugar, honey and the like are added.
Fresh fruits are occasionally used by the farmers to make sweeteners and soups during harvest season. Small amounts of the fresh fruit pulp may be eaten like candy. However, consumption of the fruit in large quantities is limited, due to the intense sweetness, and unattractive vegetable flavor.
Luo Han Guo is seldom used as fresh juice due to the problems of storing it, its unattractive vegetable flavor and its tendency to form off flavors. It has a natural pH of about 6 and it contains sugars which can brown and ferment. The pectin eventually gels on standing.
Due to the restrictions on the use of Luo Han Guo juice in particular because of the instability over time and its unattractive taste, beverages containing Luo Han Guo have not been widespread.
A process for preparing and stabilizing a concentrated Luo Han Guo juice is described in applications Downton et al, U.S. Ser. No. 08/056,459 filed May 3, 1993 now abandoned. This process makes a Cucurbitaceae fruit juice puree, serum or concentrate which is suitable for use in the subject application.
The juice has an improved flavor and is essentially free of the vegetable flavor and the bitter, astringent, brown flavor of the extracts of the dried fruit. Certain flavor characteristics of Luo Han Guo juice necessitate modification of the formulation of some edible products when the sugar is replaced in whole or in part with Luo Han Guo juice, serum or puree. For example, because the sweet component of Luo Han Guo is reported to be from about 300 to about 500 times as sweet as sucrose, use of Luo Han Guo to provide the sweetening equivalent of the sugar it replaces results in a substantial decrease in the amount of sugar needed. However, when used at concentrations equivalent to 10% to 20% sugar solutions, it also can cause a very sweet aftertaste, often described as "cloyingly" sweet or licorice-like sweetness.
The use of Luo Han Guo sweet juice, puree or serum in good tasting and storage stable beverages has not been previously disclosed. Also, the use of Luo Han Guo juice to provide additional low-calorie sweetness to otherwise unaltered beverages like lemonade, milk, milk shakes, fruit juices and fruit juice containing beverages, black tea or coffee is also not known.
Due to the instability of Luo Han Guo juice over time and its unattractive flavor, beverages containing Luo Han Guo juice have not been widespread.
The object of the subject invention is to provide a natural sweetening composition for sweetening edible products which has no sweet aftertaste or unpleasant aftertaste.
Another object of the subject invention is to provide improved low calorie edible products in which Luo Han Guo serum, puree or juice is used as a sweetening ingredient in place of sugar.
It is also an object of the present invention to provide beverages giving a sweetness perception beyond that provided by their usual sugar content. It is further desired to provide beverages with a non-caloric sweetness from a natural source, in particular to allow full or partial replacement of artificial sweeteners. In this respect it is also desirable to provide beverages useful within the dietary constraints of diabetes patients.
It also is an object of the present invention to provide reduced calorie, thirst quenching beverages comprising a flavoring system which limits the calorie content of the beverage and which contains a natural sweetening system comprising mogroside IV, mogroside V, siamenoside I or mixtures thereof and which has acceptable mouth feel and taste characteristics, particularly, a beverage without off-flavors.
It is a further object of this invention to produce a juice, and in particular, a fruit juice, which is lower in sugar and calories by blending the very sweet Cucurbitaceae juice with other fruit juices.
These and other objects of the invention are described herein.